Selected cyanomethylenecyclopropenes



United States Patent Ofiice 3,366,664 Patented Jan. 30, 1968 3,366,664 SELECTED CYANOMETHYLENECYCLOPROPENES Sam Andreades, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed Nov. 12, 1964, Ser. No. 410,747 3 Claims. (Cl. 260-465) ABSTRACT OF THE DISCLOSURE This disclosure describes and claims certain cyanomethylenecyclopropenes, e.g., 1,2-diphenyl-3 -dicyanomethylenecyclopropene and 1,2 diphenyl 3 [cyano (ethoxycarbonyl)methylene]cyclopropene, prepared by reacting cyclopropenones with active methylene compounds. The products are useful as polymerization inhibitors.

Field of the invention This invention relates to, and has as its principal objects provision of, certain novel compounds, cyanomethylenecyclopropenes.

Detailed description of the invention wherein the Rs, which can be alike or different, are hydrogen, halogen (fluorine, chlorine, bromine or iodine), nitro, alkyl or alkoxy of up to 12 carbons, or NRR", R", alike or different, being hydrogen or alkyl of up to 12 carbons. Any substituents may be ortho, meta or para to the carbon of the benzene ring attached to the cyclopropene ring except for iodo and alkyl, which may not be ortho, and there may not be two ortho substituents. A more restricted and preferred group of these novel compounds are those in which Y and Z are unsubstituted, or monosubstituted, monocyclic aryl having up to 12 carbons, and where R is lower alkyl, i.e., alkyl of 16 carbon atoms.

The compounds of the invention are prepared by contacting a cyclopropenone of the general formula none, with an active methylene compound of the general formula HnC wherein X is as above, e.g., malononitrile or ethyl cyanoacetate, at a temperature below that at which the product will decompose.

An equation for the overall reaction can thus be written as:

Yc\ /X "/C=O H20\ z-o Y-C X =C/ H2O ON ZO ON In accomplishing this reaction, the relative amounts of cyclopropenone and methylene compounds may vary from a large (e.g., S-fold) excess of ketone to a large (S-fold) excess of the active hydrogen compound. However, a moderate excess of the methylene compound (20%) is preferred.

The reaction is preferably carried out in the presence of acetic anhydride as a solvent. This compound serves to scavenge the water produced by the condensation reaction to form acetic acid, a satisfactory cosolvent for the reaction. It is not necessary to employ other cosolvents, but inert materials can be added such as cyclohexane, toluene and the like.

Temperatures used in the reaction can vary widely, e.g., from 0 to 300 C., but reflux temperature is normally used. Reflux temperature is about 140 C. for acetic anhydride at atmospheric pressure. The pressure under which the reaction is carried out is not critical. Reaction pressures ranging from subatmospheric to superatmospheric are operable, but it is generally preferable to carry out the reaction at atmospheric pressure. About two hours reaction time are required to obtain a satisfactory yield (2024%) but product is formed in 15 minutes to 24 hours.

The reaction can be carried out in the absence of a catalyst, but the yields are increased by use of an amphoteric catalyst of the type represented by ft-alanine and other amino acids, e.g., glycine, phenylalanine, leucine, etc.

Embodiments of the invention There follow some nonlimiting examples which illustrate the invention in greater detail. In these examples, pressures are atmospheric.

EXAMPLE 1 I,Z-diphenyl-S-dicyanomethylenecyclopropene OoH5--C 0N C HFC CN B-alauine /C=O H20 m l/C=C\ oars-o 3 2 115-0 ON (A) Diphenylcyclopropenone may be prepared as follows:

To a solution of 16 g. of triethylamine in 300 ml. of methylene chloride at 15-20 C. is added 18.4 g. of solid 06,0 dibromodibenzyl ketone over a period of approximately 5 min., the solution being maintained between 15-20 C. in a water bath. The solution slowly turns yellow to deep red. After 30 min., the mixture is filtered to remove the triethylammoniurn hydrobromide and the filtrate is cooled in ice for an hour and then extracted with five 300-ml. portions of cold water. The organic layer is dried over anhydrous sodium sulfate and evaporated over a rotary evaporator to a volume of about ml.

The evaporated mixture is chromatographed on 300 g. of silicic acid mesh, Mallincrodt analytical reagent). Elution with ethyl acetate first gives a small amount of red-tan material followedby 5.5 g. of yellow product. Recrystallization of the yellow product from benzene/ cyclohexane (ca. 1:4 by volume) gives material melting at l19-120 C. The mother liquors from the recrystallization can be evaporated and the residue sublimed to obtain additional material. The total yields amount to 50-60% of diphenylcyclopropenone.

3 4 (B) To 0.67 g. of diphenylcyclopropenone and 0.25 g. Analysis.-Calcd. for C H NO C, 79.71; H, 5.02; of malononitrile in 3.5 ml. of acetic anhydride was added N, 4.65; mol. wt. 301.33. Found: C, 79.36; H, 4.98; N, 0.01 g. of ,B-alanine. The mixture was refluxed for 2 hrs. 4.39; rnol. wt. 301 (mass spec), 318 (BR in benzene). and allowed to cool overnight. The mixture was chilled The infrared spectrum of this material (KBr) showed in an ice bath and filtered to collect 0.17 g. (19.5%) of 5 strong absorption at 2255, 1885, 1710, and weaker abessentially pure yellow crystals. Recrystallization from sorption at 1640, 1615 and 1587 cmf acetonitrile gave 1,2-diphenyl-3-dicyanomethylenecyclo- The proton n-m-r spectrum in deuteriochloroform (inpropene, MP. 288290 (dec.). ernally referenced from tetramethylsilane) showed bands The infrared spectrum of the product (KBr pellet) at 1.621 (area 4), 2.267 (area 6), a CH quartet at 5.367 showed stron absorption at 2230, 1870, 1600, 1517, 10 (area 2), and CH triplet at 8.621 (area 3), 1480, 1450 and 1390 crnf I The ultraviolet spectrum in acetonitrile showed the fol- CH3CH2 lowing k and 6 values: 347 (13,750), 298 (28,300), In the first column of the table below are listed spe- 286 (30,300), 267 (28,600), 261 (26,600 sh.), 252 cific cyclopropenones which, when reacted with malono- (21.25O $11.), 237.5 (18,600), 230 (17,250), and end 113- nitrile or the cyanoacetate listed in column 2 by the sorption at 220 m procedure illustrated by Examples 1 and 2, give the Analyris.-Calcd. for C H N C, 85,02; H, 3.96; N, specific cyanomethylenecyclopropenes listed in column 3.

Reactants Products Aryl Cyelopropenone Active Hydrogen Compound Cyanomethyleneoyclopropene Di(ofluorophenyl)cyclopropenoue Perfluoroethyl cyanoacetate 1,2-di(o-fiuorophenyl)-3-[eyano(perfluoroethoxycarbonyl)- methylene]cyelopropeue.

Di(m-chlorophenyl)cyclopropenone Dodecyl cyanoacetate 1,2-di(m-ehlorophenyl)-3-[cyauo(dodecyloxyearbonyDmethylcne]cyclopropene.

Di(ru-bromophenyl)eyclopropenone Malonomtrlle 1,2-di(in-bromopbenyl)-3-dicyauomethylenecyclopropene.

Di(piod0pheuyl)eyclopropenone Methyl eyanoacetate l,2-dip-iodophenyl)-3-[cyau0(methoxycarbonyl)methylene]- eyc opropene.

Di(o-toly1)eyelopropenoue Octyl eyauoacetate 1,2-(11(o-tolyl)-3-[cyano(octyloxyearbo11yl)rnothyleneleyelopropeue.

Di(m-ethylphenyl)cyelopropenoue Butyl cyauoacetate 1,2di(1m-ethylpl1e11yl)-3-[cya110(butoxycarbonyl)methylene]- eyc opropeue.

Di(p-n-hexylphenyl)cyelopropenone Malononitrile 1,2-di(p-u-hexylphenyl)-3-dicyanomethylenecyelopropeue.

Di(p-dodecylpheuyl)eyclopropenone do 1,2-di(p-d0decylphe11yl)-3-dicyanomethyleueoyclopropeue.

Di(m-dimethylaminophenyl)cyclopropeuone fi-Fluoroethyl eyan0aeetate 1,2-di(m-dirnethylmniuophenyl)-3-[cyano-(B-lluoroethoxybouyl)methyleue]cyclopropene.

Di(p-methoxypheuyl)eyelopropenoue HeXyl cyanoacetate 1,2-di(p-methoxyphenyl)-3-[oyauo(hexyloxycarbonyl)methyl eno]cyclopropeno.

Di(o-uitropheuyleyclopropenone a,a-Dlhydroperfluoropropylcyan- 1,2-di(o-nitrophenyl)-3-[eyauo-(a,a-dihydroperfiuoroprooaeetate. poxyearbonyl)methyleue]cyclopropene.

I)i(p-methoxy m-methylphenyl)cyelopropenone. Malononitrile 1,2-di (p-methoxy-m-methylpheny1)-3-dicyanomethyleneeyclopropeue.

11.02; mol. wt. 254.27. Found: C, 85.39; H, 3.74; N, The cyclopropenoue reactants used in the process of 11.04; mol. wt. 254 (mass spec), 250 (vapor pressure this invention can be prepared by the method illustrated osmometry in CHCI in Example 1, part A, and as described by Breslow,

(C) Evaporation to dryness of the filtrate from a Posner and Krebs, J. Am. Chem. Soc., 85, 234 (1963).

5-g. run of B and sublimation of the residue at 198 (0.1 The active hydrogen reactants, i.e., malononitrile and mm.) gives 2.3 g. of white sublimate from which was alkyl or fluoroalkyl cyanoacetates, are readily available isolated 0.08 g. of trans-ix-phenylcinnamic acid, M1. 169 or can be made by well-known methods.

171 (lit., M.P. 172). The infrared spectrum of this The compounds of this invention have various utilities.

sample was identical to that of an authentic sample. More particularly, they are useful as polymerization (D) Using 93.23 mg. of 1,2-diphenyl-3-dicyanometh- 0 inhibitors. For example, trace amounts of 1,2-diphenylylenecyclopropene, 15 mg. of palladium-on-charcoal, 5O 3-dicyanomethylenecyclopropene, prepared as in EX- mg. of sodium carbonate and 25 ml. of ethanol, 0.0138 g. ample 1, were found to inhibit the polymerization of H g. of sample was consumed indicating reduction to acrylonitrile containing azobis(isobutyronitrile) under the extent of 1.8 double bonds/molecule. conditions which caused the rapid polymerization of EXAMPLE 2 acrylonitrile control samples. The conditions were 5-15 min. at the temperature of refluxing acrylonltrile. The

p y -[W y y y l y methylenecyclopropenes are also generically useful as propane ultraviolet light absorbers and as electrical insulators.

CGHFC COOCZH, Another utility of the present methylenecyclopropenes +1120 Iii-alanine is as chlorine scavengers and detectors. When chlorine (OH3C0)2( gas is bubbled lnto an acetonitrile slurry of the dicyano- COHFC 0N or the cyano(ethoxycarbonyl)methylenecyclopropene de- OGI'IE C COOCHI'IIS rivatives, a smooth and quantitative reaction with chlorine occurs at room temperature. The reaction is obcGHFG/ served not only by a color change from orange to a light yellow, but also by the change from a heterogeneous A mlXtllre of of P y Y P P and 4- mixture to a homogeneous solution. The latter phen0rney oyanoaootato 111 of aoetlo anhydndo non is due to the greater solubility of the dichloro derivacontaining a trace of ,B-alanrne was refluxed for 3 hrs. fi compared to h methylenecyclopropenes,

under y mtrogon- The hot homogeneous Solotlon Was Since obvious modifications and equivalents in the inallowed o cool slowly and finally chilled in ice vention will be evident to those skilled in the chemical tlon gavo g of P Y Y arts, I propose to be bound solely by the appended claims. y y y l y p p 4 The embodiments of the invention in which an exclu- Recrystallization from benzene/hexane (1:1) gave a samsive property or privilege is claimed are defined as folple, M.P. 159-160 lows:

1. A cyanomethylenecyclopropene of the formula X is selected from the group consisting of CN and COOR, R being selected from the group consisting of alkyl and fluoroalkyl of up to 12 carbons; and

Y and Z are monocyclic aryl of up to 18 carbons having the formula R R the R"s being selected from the group consisting of hydrogen, halogen, nitro, alkyl and alkoxy of up to 12 carbon and NR"R", R" being selected from the group consisting of hydrogen and alkylof up to 12 carbons, one R in the ortho position always being hydrogen and neither being selected from the group consisting of iodo and alkyl.

2. 1,2-diphenyl-3dicyanomethylenecyclopropene.

3. 1,2 diphenyl-3-[cyano(ethoxycarbonyl)rnethylene] cyclopropene.

References Cited UNITED STATES PATENTS 12/1965 Hartzler 260-465 X OTHER REFERENCES Battiste, J.A.C.S., 86, pp. 942, 943 (1964).

Jones, 'et al., J.A.C.S., 86, pp. 944, 945 (1964). Bergmann et al., J.A.C.S., 86, p. 3587 (1964). Kende et al., J.A.C.S., 86, pp. 3587-3589 (1964).

JOSEPH P. BRUST, Primary Examiner. 

